In recent years, televisions (television receivers) and PCs (Personal Computers) installed with an interface conforming to the HDMI (High-Definition Multimedia Interface) (registered trademark) standard have become widespread, and it is becoming common to connect these sink apparatuses with source apparatuses (e.g. AV devices) via an HDMI cable. A sink apparatus and a source apparatus connected to each other via the HDMI cable are capable of transmitting and receiving not only video signals and audio signals but also CEC (Consumer Electronics Control) commands to each other.
The CEC commands transmitted and received between devices and apparatuses connected via the HDMI cable include, as arguments, a logical address and/or a physical address of an initiator and/or a destination. The devices and apparatuses connected via the HDMI cable identify the initiator and/or the destination of a CEC command based on the logical address and/or physical address contained in that CEC command.
The logical address here is represented by a natural number from 1 to 15, each of which indicates a kind of apparatus (any one of television (TV), recording device, playback device, tuner device, audio device, or other kind of apparatus). For example, a logical address “0” represents a TV, a logical address “1” represents a first recording device, and a logical address “2” represents a second recording device.
Use of the CEC command allows controlling a source apparatus from a sink apparatus and controlling a sink apparatus from a source apparatus. Thereby, the use of the CEC command allows the users to enjoy convenience, which have not been provided so far. For example, it is possible to automatically switch an input source for the sink apparatus to a source apparatus that has started to playback content. See Non Patent Literature 1 for details of HDMI.
Patent Literature 1 discloses a technique of displaying on a portable phone terminal a user interface for operating (controlling) a TV. By use of the technique disclosed in Patent Literature 1, it is possible to operate (control) a TV with use of a portable phone terminal, without manipulating the TV or the remote controller of the TV.